Question 1

After reading the paragraph below, answer the question that follows.
Rice is a staple crop across Asia; it serves as a main nutritional source for Asia's high population. In the 1970s, a pathogen called the grassy-stunt virus greatly decreased cultivated rice plant populations. Scientists found one wild relative of the rice plant in India that was resistant to the grassy-stunt virus, and today hybrid rice plants with that resistant gene are grown across Asia. To find this one rice plant species, approximately 17,000 rice plants samples were tested over the course of four years.
-If you were a scientist working on this project, how would you argue that the results of the research would be worth the time investment?

Accepted Answer

The paragraph states that rice serves as a main nutritional source for Asia's high population and that hybrid rice plants with the resistant gene are grown across Asia. Therefore, finding the wild relative with disease resistance would allow Asian farmers to continue to grow the crop they know, ensuring a stable food source for the population. The other choices are not supported or mentioned by the paragraph.

Question 2

According to this figure, which organisms have the highest concentration of PCBs, and why?

Accepted Answer

PCBs bioaccumulate as they move up the food chain, so organisms at higher trophic levels (such as herring gulls) will have higher concentrations of PCBs than those at lower trophic levels (such as phytoplankton). Smelt are in the middle of the food chain and would have intermediate concentrations of PCBs.

Question 3

You are a climate scientist who wants to investigate climate change. Which of the following measurements would be the least useful?

Accepted Answer

Methane levels from dairy farms in Iowa during the specific years of 2011 and 2012 may not provide a comprehensive picture of overall climate change, as they only represent a small area and a short time period. The other options provide long-term and/or broader measurements and therefore would be more useful in investigating climate change.

Question 4

While habitat destruction by humans creates fragmented ecosystems, fragmentation can also occur due to natural processes. Which of the following natural processes would most likely create a fragmented ecosystem?

Accepted Answer

The answer of While habitat destruction by humans creates fragmented...

Question 5

The figure below depicts natural fluctuation of ozone levels in Switzerland between 1925 and 1976. Dobson units are a way to measure the total amount of atmospheric ozone above a point on the Earth's surface. 
What can you conclude from this figure?

Accepted Answer

The figure shows that ozone levels fluctuate year to year and do not follow a distinct pattern. The average for the 50-year span appears to be around 330 Dobson units, as this is the value to which the line generally seems to oscillate around. However, there are periods where the value is higher or lower than this. The figure does not provide information about whether Switzerland is a model example or whether all small European countries will show fluctuations in ozone concentration levels.

Question 6

After reading the paragraph below, answer the questions that follow.
As the climate warms, organisms will shift their population ranges to different areas that are cooler. However, as humans continue to fragment large tracts of land, species will face increasing challenges in adapting their ranges to new climates. For example, movement corridors may not be able to be built if the amount of land needed for a species' range is fragmented due to cities and roads. One alternative to creating movement corridors is called managed relocation. This requires physically moving species to cooler climates.
-Which of the following is an advantage of using managed relocation?

Accepted Answer

Managed relocation can potentially reduce the need for large conserved areas and corridors, thus lowering the costs associated with maintaining these areas.

Question 7

In Clackamas, Oregon, a stand of hybrid poplar trees was planted on an area of land that is contaminated with volatile organic compounds (VOCs). Why would someone purposely plant trees in an area with contaminated soil?

Accepted Answer

Planting certain types of trees, such as hybrid poplars, can be a form of phytoremediation in which the trees absorb and break down contaminants in the soil through their roots and leaves. This helps to purify the soil and make it safe for other types of plants or for development.

Question 8

Which of the following is not an example of a predicted impact of climate change?

Accepted Answer

This is not an example of a predicted impact of climate change as it suggests an increase in wildflower diversity in northeastern United States, which is not necessarily correlated with climate change. The other options are examples of predicted impacts of climate change, such as increased severity of wildfires, higher temperatures in spring, and greater loss of marine life in Australian coral reefs as a result of rising ocean temperatures.

Question 9

Suppose a species of wild boar (a type of pig)is actively hunted when it is at a young age because at that stage of its development the meat of the boar is particularly tender. What is a likely outcome if this species is overharvested?

Accepted Answer

Overharvesting young boars will decrease the overall breeding population of the species. Eventually, this can lead to a decline in population, especially if the number of females left able to produce offspring is limited. The remaining population will consist of older boars, which will not be as productive for hunting purposes, and may not be enough to sustain an adequate population size.

Question 10

After reading the paragraphs below, answer the questions that follow.
Introduced species are a problem all over the world, and there are many examples in the United States. Several years ago, a fisherman caught a northern snakehead fish in a pond in Crofton, Maryland (a suburb of Washington, DC). Snakeheads are a favorite food of immigrants from China, and live fish can frequently be found in Asian markets. It was suspected that the fish in the Crofton pond were purchased locally and then intentionally released.
Snakeheads are top predators, and 90% of the northern snakeheads' diet consists of other fishes. The northern snakehead can breathe out of water and travel short distances (about 100 feet) across land. They also breed rapidly. Females can lay more than 100,000 eggs per year. Juveniles have also been identified in the Potomac River and other rivers in Pennsylvania.
-Based on the characteristics of the snakehead described, which of the following is most likely to be a productive strategy to reduce the spread of this species?

Accepted Answer

Introducing a natural predator to feed on juvenile snakeheads is the most likely to be a productive strategy to reduce the spread of this species because it would reduce the number of juvenile snakeheads that survive to adulthood and reproduce.

Question 11

Araschnia levana is a species of butterfly that breeds several times a year. It has two distinctly colored pupae: Those that emerge in spring are orange and those that emerge in summer are brown. The seasonal color variations in pupae mean that the pupae blend into the colors in their environment. This is an example of

Accepted Answer

The seasonal color variations in pupae of Araschnia levana are an example of phenotypic plasticity, which refers to the ability of an organism to produce different phenotypes in response to changes in its environment.

Question 12

According to this graph of changes in Earth's atmosphere, which of the following took place between the years 1800 and 2000?

Accepted Answer

The graph shows an increase in carbon dioxide levels from around 290 ppm to 380 ppm between 1800 and 2000.

Question 13

After reading the paragraph below, answer the questions that follow.
As the climate warms, organisms will shift their population ranges to different areas that are cooler. However, as humans continue to fragment large tracts of land, species will face increasing challenges in adapting their ranges to new climates. For example, movement corridors may not be able to be built if the amount of land needed for a species' range is fragmented due to cities and roads. One alternative to creating movement corridors is called managed relocation. This requires physically moving species to cooler climates.
-Which of the following is a disadvantage of using managed relocation?

Accepted Answer

Managed relocation may result in moving species to new areas where they may become invasive and disrupt the ecosystem. The other answer choices are not stated in the paragraph.

Question 14

As global temperatures continue to rise, what is a likely outcome?

Accepted Answer

Warmer water temperatures can lead to decreased oxygen levels in bodies of water, which can cause fish populations to decline. Additionally, changing ocean currents and water temperatures can also lead to shifts in the distribution of fish species, potentially causing some to become endangered or extinct.

Answer: B
 As temperatures rise, some medicinal plant species may struggle to survive due to shifting climate patterns or changing weather conditions. This could lead to overharvesting of remaining populations, as people try to obtain increasingly scarce resources.

Answer: C
 While reducing greenhouse gas emissions is crucial for mitigating the impacts of climate change, it is unlikely to be a direct outcome of rising temperatures on its own.

Answer: D
 It is unlikely that new glaciers will form as temperatures rise, as glacial melt is typically accelerated by warmer temperatures. Additionally, melting glaciers can have significant impacts on ecosystems, such as altering water cycles and causing flooding.

Question 15

If current trends in global warming continue for the next 50 years, where will the greatest effects of global warming likely be felt?

Accepted Answer

The answer of If current trends in global warming continue...

Question 16

After reading the paragraphs below, answer the questions that follow.
Introduced species are a problem all over the world, and there are many examples in the United States. Several years ago, a fisherman caught a northern snakehead fish in a pond in Crofton, Maryland (a suburb of Washington, DC). Snakeheads are a favorite food of immigrants from China, and live fish can frequently be found in Asian markets. It was suspected that the fish in the Crofton pond were purchased locally and then intentionally released.
Snakeheads are top predators, and 90% of the northern snakeheads' diet consists of other fishes. The northern snakehead can breathe out of water and travel short distances (about 100 feet) across land. They also breed rapidly. Females can lay more than 100,000 eggs per year. Juveniles have also been identified in the Potomac River and other rivers in Pennsylvania.
-When snakeheads enter aquatic ecosystems, biodiversity in these ecosystems would most likely

Accepted Answer

Snakeheads are top predators and their diet consists mainly of other fishes. When they enter new ecosystems, they are likely to prey on native species, leading to a decrease in biodiversity.

Question 17

Sustainable development

Accepted Answer

Sustainable development is a global issue that affects every country, and no single nation can tackle it alone. Hence, sustainable development will require global, multinational cooperation, with each country working together to find solutions to the world's most pressing economic, social, and environmental challenges.

Quiz 38: Conservation Biology